Bulk and CC-Tape Based Superconducting Shields for Magnetic Cloaks

Two-shell scheme consisting of an outer ferromagnetic tube and an inner superconducting cylinder was experimentally verified as a promising design concept for making magnetic cloaks of centimeter size. Because some applications may require bigger sizes of the shielded volume, scalability of dimensions is an important parameter in the assessment of various options for cloak design. It is easy to prepare uniform ferromagnetic tubes with diameters exceeding several centimeters. On the other hand, producing a superconducting shield with comparable dimensions is not trivial. In the present work, we examined two types of superconducting inserts. The first type is the hollow cylinder made from the bulk superconducting material-BSCCO-2212. In the second type, there are 12 mm wide coated conductor tapes helically wound on the fiberglass former forming the shielding layers. Both superconducting cylinders with identical inner diameter 43 mm and length 145 mm were tested in low frequency ac magnetic field. We compare the shielding properties and the complex magnetic susceptibility of these inserts.